An intermediate symbol buffer (ISB) configuration and method is provided such that the ISB memory comprises 15 portions, one for each HSDPA spreading code. Symbols associated with a spreading code are written to the memory portion associated with the same spreading code. When a covariance calculation is performed to obtain a more accurate channel estimate, only the symbols associated with spreading codes determined to be needed for the covariance calculation are written to the ISB by a buffer block and red from the ISB by a correlation core. The symbols associated with spreading codes that are not necessary for a covariance calculation may be masked from being written or read from the ISB. In some embodiments each memory portion is an individual memory block. In other embodiments a plurality of memory blocks may contain a plurality of memory portions, one memory partition designated, at least temporarily, for each spreading code.